Letter from Harold Perot Keen, treasurer of the Vacuum Refrigeration Company to William du Pont Sr. regarding payment of the company's bills. Letterhead notes William du Pont as the company's Vice President.

Table of Contents: The Supremacy of Service; Service Department of the New York Paint Office; Lactic Acid; T.N.T.; Dynamite and Loganberries; The Manufacture and Uses of Py-ra-lin; Country Dealer's Opportunity; Clean Collars without Laundry Bills;...

Letter from William du Pont to his father while attending MIT. In addition to asking for more money on account of his doctor's bills and clothes washing, William expresses concern over passing his upcoming examinations, though he says he will do...